Pretty much ALL fighting game spin-offs suck, if they expect to be driven by story at all.

I chalk it up to fighting games being based on action instead of story, but when they try to expand the story of one or more characters in any other game genre, there's just not enough meat to make the game compelling. The only exception would be puzzle games or other pure-action games where story doesn't matter (Puzzle Fighter, the Capcom vs. Psikyo mahjongg game, Gunspike/Cannon Spike, etc.)

Look at the Samurai Spirits RPG, the animated Street Fighter quest game, etc. for more examples of how these spin-offs generally don't work well.